release: v0.2.4 里程碑快照（孤儿提交，无父；树 = dev 68362e5）

本批内容见 CHANGELOG.md 的 0.2.4 段。按 D41 用孤儿快照推 main，保留「公开史只有里程碑」的模型。

crates/presenter/src/dto/adopt/tests.rs

@@ -0,0 +1,136 @@
+//! `dto::adopt` 的 IPC 契约用例（M223 从 `dto/adopt.rs` **纯搬移**，断言一条未改）。
+//!
+//! 为什么搬：`dto/adopt.rs` 落笔 512 行，越过 400 行硬线（AGENTS §3.1）；口径与
+//! [`crate::dto::events::tests`] 完全一致——**纯搬移、一行不改**。`adopt.rs` 是非 `mod.rs`
+//! 文件，`mod tests;` 的落点就是本文件。
+
+use super::*;
+
+fn candidate(version_id: &str, problems: Vec<AdoptProblemView>) -> AdoptCandidateView {
+    AdoptCandidateView {
+        version_id: version_id.to_string(),
+        jar_present: true,
+        inherits: Vec::new(),
+        registered: Vec::new(),
+        problems,
+    }
+}
+
+fn scan_view() -> AdoptScanView {
+    AdoptScanView {
+        versions_dir: PathBuf::from("/game/versions"),
+        candidates: vec![
+            candidate("1.20.1", Vec::new()),
+            candidate(
+                "1.19.4",
+                vec![AdoptProblemView {
+                    code: "manifest_missing".to_string(),
+                    message: "版本 1.19.4 没有清单文件".to_string(),
+                }],
+            ),
+        ],
+    }
+}
+
+#[test]
+fn events_round_trip_through_json() {
+    let event = AdoptEvent::Failed(Box::new(AdoptFailureView {
+        code: "adopt_not_adoptable".to_string(),
+        message: "版本 1.19.4 不能登记".to_string(),
+        problems: vec![AdoptProblemView {
+            code: "manifest_missing".to_string(),
+            message: "清单缺了".to_string(),
+        }],
+    }));
+    let text = serde_json::to_string(&event).expect("序列化");
+    assert_eq!(
+        serde_json::from_str::<AdoptEvent>(&text).expect("反序列化"),
+        event
+    );
+
+    let command = AdoptCommand::Preview(Box::new(AdoptRequestView {
+        version_id: "1.20.1".to_string(),
+        name: Some("生存".to_string()),
+        target: AdoptTargetView::Shared,
+    }));
+    let text = serde_json::to_string(&command).expect("序列化");
+    assert_eq!(
+        serde_json::from_str::<AdoptCommand>(&text).expect("反序列化"),
+        command
+    );
+}
+
+#[test]
+fn scan_summarises_adoptable_and_empty() {
+    let view = scan_view();
+    assert_eq!(view.total(), 2);
+    assert_eq!(view.adoptable(), 1);
+    assert!(!view.is_empty());
+    assert!(AdoptScanView {
+        versions_dir: PathBuf::from("/game/versions"),
+        candidates: Vec::new(),
+    }
+    .is_empty());
+}
+
+#[test]
+fn target_slugs_round_trip_and_mark_foreign_dirs() {
+    for target in AdoptTargetView::ALL {
+        assert_eq!(AdoptTargetView::from_slug(target.slug()), Some(target));
+    }
+    assert_eq!(AdoptTargetView::default(), AdoptTargetView::InstanceDir);
+    assert!(!AdoptTargetView::InstanceDir.touches_foreign_dir());
+    assert!(AdoptTargetView::Shared.touches_foreign_dir());
+    assert!(AdoptTargetView::VersionDir.touches_foreign_dir());
+}
+
+#[test]
+fn state_follows_the_four_stages() {
+    let mut state = AdoptState::default();
+    assert_eq!(state.stage(), AdoptStage::Pick);
+
+    state.apply(AdoptEvent::Scan(Box::new(scan_view())));
+    assert_eq!(state.stage(), AdoptStage::Pick);
+    assert_eq!(state.scan.as_ref().map(AdoptScanView::adoptable), Some(1));
+
+    let plan = AdoptPlanView {
+        version_id: "1.20.1".to_string(),
+        name: "1.20.1".to_string(),
+        target: AdoptTargetView::InstanceDir,
+        isolation: AdoptIsolationView::Custom,
+        run_dir: PathBuf::from("/ull/data/instances/1.20.1"),
+        notes: vec!["运行目录 = /ull/data/instances/1.20.1".to_string()],
+    };
+    state.apply(AdoptEvent::Planned(Box::new(plan.clone())));
+    assert_eq!(state.stage(), AdoptStage::Preview);
+    assert_eq!(
+        state.plan.as_ref().map(|plan| &plan.run_dir),
+        Some(&plan.run_dir)
+    );
+
+    // 失败会把预检顶掉：留着预检，确认按钮就会在「不能登记」的结论上继续亮着
+    state.apply(AdoptEvent::Failed(Box::new(AdoptFailureView {
+        code: "adopt_duplicate_name".to_string(),
+        message: "已有同名实例".to_string(),
+        problems: Vec::new(),
+    })));
+    assert_eq!(state.stage(), AdoptStage::Failed);
+    assert!(state.plan.is_none());
+
+    state.apply(AdoptEvent::Done(Box::new(AdoptDoneView {
+        instance_id: "id-1".to_string(),
+        name: "1.20.1".to_string(),
+        version_id: "1.20.1".to_string(),
+        isolation: AdoptIsolationView::Custom,
+        run_dir: PathBuf::from("/ull/data/instances/1.20.1"),
+        dir_created: true,
+        notes: Vec::new(),
+    })));
+    assert_eq!(state.stage(), AdoptStage::Done);
+    assert!(state.failure.is_none());
+
+    // 关面板 = 全清（再开要重新扫，否则画的是上一轮的候选）
+    state.apply(AdoptEvent::Cleared);
+    assert_eq!(state.stage(), AdoptStage::Pick);
+    assert!(state.scan.is_none() && state.done.is_none());
+}